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  • 1.
    Rothhämel, Malte
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik.
    Capturing steering feel: a step towards implementation of active steering in heavy vehicles2010Licentiatavhandling, med artikler (Annet vitenskapelig)
  • 2.
    Rothhämel, Malte
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik.
    Characterisation and Utilisation of Steering Feel in Heavy Trucks2013Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Steering is next to braking the most important control feature of a road vehicle. The driver gives input through the steering wheel and the vehicle reacts in a certain way, which results in a transfer function between input and output. The transfer function can be modified by means of an actuator in the steering system to improve safety, handling and steering feel. To be able to use active steering systems to improve the steering feel, we need to understand how steering feel comes about. There have been several investigations to find out how drivers experience a change in vehicle steering and handling behaviour and how a change in vehicle handling behaviour affects the driver. However, as yet, there is no standardised way to find mutual corresponding measurements, assessments and ratings, nor is there a consistent definition of steering feel. An important part of investigating steering feel concerns how to measure what drivers feel. One of the essential prerequisites in the present research work is that steering feel, as perceived by human beings, can be allotted in dimensions. To define this non-instrumental space, a method to find the dimensions that people use to perceive and describe steering feel has been developed. It is shown that it is possible to extract up to nine dimensions describing the steering feel of road vehicles. This was experimentally evaluated using a driving simulator. In the test, drivers assessed truck steering system settings that differed in friction, damping, inertia and stiffness, due to five dimensions of steering feel. The same steering system settings were also tested in accordance with ISO standards for vehicle handling to acquire characteristic instrumental quantities. The instrumental measurements and the non-instrumental assessments were then analysed with respect to their correlation with each other. The results show that there are indeed correlations and also which of the handling quantities influence which dimension of steering feel.One possible use of the increased knowledge of steering feel evaluation is to influence the driver's behaviour by a directed change of steering feel. In a track test the steering wheel torque of a truck was modified depending on the lateral dynamic vehicle driving state. During the experiment the cornering behaviour of truck drivers was evaluated regarding lateral acceleration, which is related to rollover accidents. Statistical evaluation showed a decrease of maximum lateral acceleration values while cornering when the steering wheel torque was decreased at high lateral acceleration. There are also more possibilities to modify the transfer function between driver input and vehicle response. Artificial understeering and yaw rate gain acceleration are two functionalities that were developed during this work and were evaluated by simulation. Thus, based on the knowledge about steering feel, an application-oriented hypothesis could be formulated and evaluated. The fundamental part of this thesis contributed a puzzle piece to the mapping of steering feel while the advanced part established ties to future applications with active and semi-active steering as well as driver assistance systems.

  • 3.
    Rothhämel, Malte
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik.
    Fail-operational vehicle dynamics for autonomous operation—A review through other engineering domains2018Inngår i: The Dynamics of Vehicles on Roads and Tracks, CRC Press/Balkema , 2018, s. 491-496Konferansepaper (Fagfellevurdert)
    Abstract [en]

    For vehicles in autonomous operation, fail-operational chassis components will be needed. ISO 26262 gives guidelines on how to proceed in the development process, however, it does not provide technical solutions. Anyhow, there are fail-operational systems realized in other domains from which to get inspiration. Agriculture, railway, aviation and naval systems are shown here as examples. Experience shows that an overview of rules and standards and approaches in other domains opens our eyes for practical solutions.

  • 4.
    Rothhämel, Malte
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik.
    Drugge, Lars
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik.
    IJkema, Jolle
    Scania AB.
    Finding correlation between handling values and the drivers’ performance using a moving base driving simulator2011Inngår i: Proceedings of the 22st International Symposium: Dynamics of Vehicles on Roads and Tracks, 2011Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This work presents the evaluation of an experiment on the relationship between driver performance and vehicle handling quantities. Both of them are instrumental quantities, however, the former are driver dependent, the latter are only vehicle dependent. A moving base driving simulator was used to examine 16 truck-trailer-combinations. The driving of 28 test drivers in a special developed manoeuvre resulted in characteristic driver performance values evaluated of vehicle system quantities measured while driving. Stationary and dynamical ISO-handling tests resulted in handling quantities. The correlation by means of regression analysis between these driver performance values and the quantities of the ISO-handling tests are presented here as a step towards the mapping of steering feel.

  • 5.
    Rothhämel, Malte
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik.
    IJkema, Jolle
    Scania CV AB.
    Drugge, Lars
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik.
    A method to find correlations between steering feel and vehicle handling properties using a moving base driving simulator2011Inngår i: Vehicle System Dynamics, ISSN 0042-3114, E-ISSN 1744-5159, Vol. 49, nr 12, s. 1837-1854Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    There have been several investigations to find out how drivers experience a change in vehicle-handling behaviour. However, the hypothesis that there is a correlation between what the driver perceives and vehicle-handling properties remains to be verified. To define what people feel, the human feeling of steering systems was divided into dimensions of perception. Then 28 test drivers rated different steering system characteristics of a semi-trailer tractor combination in a moving base-driving simulator. Characteristics of the steering system differed in friction, damping, inertia and stiffness. The same steering system characteristics were also tested in accordance with international standards of vehicle-handling tests resulting in characteristic quantities. The instrumental measurements and the non-instrumental ratings were analysed with respect to correlation between each other with the help of regression analysis and neural networks. Results show that there are correlations between measurements and ratings. Moreover, it is shown that which one of the handling variables influence the different dimensions of the steering feel.

  • 6.
    Rothhämel, Malte
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik.
    Ijkema, Jolle
    Scania.
    Drugge, Lars
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik.
    Artificial understeer by means of active steering: an investigation of proper handling test methods2013Inngår i: Proceedings of the 23rd Symposium of the International Association for Vehicle System Dynamics, 2013Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper shows for a heavy truck simulation model the advantages of an artificial understeering functionality realised by a PID controlled active front steering system based on linear calculated yaw rate error. The yaw rate error results from the difference between measured vehicle yaw rate and a linear calculated yaw rate based on steering wheel angle and vehicle speed. The integrated controlled system shows increased performances: The more linear-like behaviour together with a higher understeer gradient over a wide lateral acceleration range which increases safety especially in emergency conditions.

  • 7.
    Rothhämel, Malte
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik.
    IJkema, Jolle
    Scania AB.
    Drugge, Lars
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik.
    Finding correlation between steering feel assessments and the driver’s performance using a moving base driving simulator2011Inngår i: FAST-zero’11, Society of Automotive Engineers, 2011Konferansepaper (Fagfellevurdert)
    Abstract [en]

    There is not yet a standardised method to find mutual corresponding subjective and objective measurements. This paper describes how non-instrumental measurements (made by human measurement gauges) and instrumental measurements (made by measuring instruments) can be distinguished in quantities that are dependent of the vehicle, the driver's skills or the driver's individual preferences. Moreover, this paper shows the correlation between instrumental and non-instrumental measurements.

  • 8.
    Rothhämel, Malte
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik.
    Ijkema, Jolle
    Drugge, Lars
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik.
    Influencing driver chosen cornering speed by means of modified steering feel2014Inngår i: Vehicle System Dynamics, ISSN 0042-3114, E-ISSN 1744-5159, Vol. 52, nr 4, s. 522-538Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper presents an investigation about influencing the driver's behaviour intuitively by means of modified steering feel. For a rollover indication through haptic feedback a model was developed and tested that returned a warning to the driver about too high vehicle speed. This was realised by modifying the experienced steering wheel torque as a function of the lateral acceleration. The hypothesis for this work was that drivers of heavy vehicles will perform with more margin of safety to the rollover threshold if the steering feel is altered by means of decreased or additionally increased steering wheel torque at high lateral acceleration. Therefore, the model was implemented in a test truck with active steering with torque overlay and used for a track test. Thirty-three drivers took part in the investigation that showed, depending on the parameter setting, a significant decrease of lateral acceleration while cornering.

  • 9.
    Rothhämel, Malte
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik.
    IJkema, Jolle
    Scania CV AB.
    Drugge, Lars
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik.
    On a Method for Generating a Word Pool for the Description of Steering Feel2010Inngår i: AVEC 10 - Proceedings, 2010Konferansepaper (Fagfellevurdert)
    Abstract [en]

    “If touching is not a single perception but a plural, then its objects are a plurality, too.” (Aristotle)

    For investigating steering feel, a very important part is how to measure what people feel. The hypothesis in the present research work is that steering feel, as perceived by human beings, can be allotted in dimensions. The steering feel of a certain vehicle can then be seen as a point in a space with multiple orthogonal dimensions. The aim is to find the dimensions that people use to perceive and describe steering feel, in order to define this non-instrumental space. This article describes two modes of evaluation, a manual mode anda mathematical mode using the statistical method of multidimensional scaling. Applying these modes, it has been possible to extract nine dimensions describing the steering feel of road vehicles.

  • 10.
    Rothhämel, Malte
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik.
    IJkema, Jolle
    Scania CV AB.
    Drugge, Lars
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik.
    On the correlation between steering feel and handling in heavy trucks2008Inngår i: FISITA World Automotive Congress 2008, Congress Proceedings - Mobility Concepts, Man Machine Interface, Process Challenges, Virtual Reality: Volume 1, 2008, s. 311-317Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Driving a car gives us a certain feeling. Driving another car returns a very differentexperience. If we could drive with closed eyes, we could nonetheless explain which vehicle itwas we were sitting in. Not only are there differences between sports cars and transporters orlimousines and trucks, but also it is possible to feel the different sensations from drivingtrucks of different manufacturers. It depends on the seat, the sitting position, the view, thesound, the performance, the brakes - and the steering feel.There are many ways how to describe a vehicle's steering feel. There are ISO-standards, suchas ISO/TS 20119 and ISO 14792 that generate characteristic values, there are subjective testsof automotive magazines, and there are opinions of test and race drivers. But exactly there,between the pure objective tests and the subjective impressions that are difficult to describe,exists a gap. This relationship between instrumentally measured numbers and nearlyindescribable feelings has not been fully investigated yet. With a better understanding of thecorrelation between objective values and subjective experience, it may be possible to find ananswer on which parameters can manipulate the feelings.This paper is on an investigation about finding a correlation between instrumental values(values measured by instruments or calculated from those) and non-instrumental values(values obtained by human impressions). The idea is to use drivers as human measuringgauges and let them measure impressions in their own words.Thus, in order to gather a standardized answer that can be evaluated, a questionnaire wasdeveloped. For this questionnaire the most important consideration was to facilitate the testdrivers with their own languages. Therefore, the questions were developed in the test drivers'native language. The characteristic words were chosen corresponding to the results of adouble interrogation process.When people express their feelings like they are accustomed to do, they will utilize a libraryof expressive words instead of numbers. Thus the measuring results will have that character,too. By using the semantic differential method, expressions can be translated into numbers.The semantic differential method is a well-known method especially in psychoacousticswhich allows people describe how noise sounds to them. With this kind of evaluation - valueassigning procedure - a list of parameters comes to existence similar to that containing theinstrumental values. To explore the relation between the instrumental and non-instrumentalvalues, statistical methods are used.

  • 11.
    Stensson Trigell, Annika
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik. KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellence Center for ECO2 Vehicle design.
    Rothhämel, Malte
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg.
    Pauwelussen, Joop
    Kural, Karel
    Advanced vehicle dynamics of heavy trucks with the perspective of road safety2017Inngår i: Vehicle System Dynamics, ISSN 0042-3114, E-ISSN 1744-5159, Vol. 55, nr 10, s. 1572-1617Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper presents state-of-the art within advanced vehicle dynamics of heavy trucks with the perspective of road safety. The most common accidents with heavy trucks involved are truck against passenger cars. Safety critical situations are for example loss of control (such as rollover and lateral stability) and a majority of these occur during speed when cornering. Other critical situations are avoidance manoeuvre and road edge recovery. The dynamic behaviour of heavy trucks have significant differences compared to passenger cars and as a consequence, successful application of vehicle dynamic functions for enhanced safety of trucks might differ from the functions in passenger cars. Here, the differences between vehicle dynamics of heavy trucks and passenger cars are clarified. Advanced vehicle dynamics solutions with the perspective of road safety of trucks are presented, beginning with the topic vehicle stability, followed by the steering system, the braking system and driver assistance systems that differ in some way from that of passenger cars as well.

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